In thread-storage and supply devices, in which the thread is tangentially wound upon the storage drum by means of the feed element which is set in rotation and is thereafter withdrawn at the top, the storage drum itself must not execute any rotation, since the thread would otherwise be undesirably twisted. The rotating feed element and the unwinding thread, however, make it impossible to grip and stationarily hold the storage drum, which itself is mounted on the rotating shaft, from any external position, i.e, from the base body. Hence, other precautions are known which attempt to hold the stoarge drum stationary. These, however, all involve a considerable technical outlay.
A thread-storage and delivery device is known from German OS No. 23 52 521, in which the drum holding mechanism consists of a permanent magnet which is arranged in the storage drum and a permanent magnet which is fastened stationarily in the machine frame. This magnet pair act on one another for holding the storage drum stationary on the shaft which supports it. However, for thick threads, a relatively large air gap must be provided between the magnets, which thus requires strong and heavy magnets. These undesirably increase not only the weight of the entire device, but also make access to the drum jacket more difficult since, for example, several magnet pairs are distributed over the periphery. During adjusting of the device or during a breakdown in operation, good accessibility to the drum jacket is especially of importance. Also, the permanent magnets can never hold the drum totally stationary. Rather, rotary oscillations of the drum result in undesired tension variations in the unwinding thread. It is furthermore disadvantageous in this known device that the wobbling disk is indirectly held against rotation through a toothed engagement with the drum jacket. Teeth of the wobbling disk loosely engage within windows of the drum jacket, wherein each tooth--in relationship to its window--carries out an elliptical movement, which during the engagement leads to a characteristic motion component which lies in the direction of rotation. Thus the wobbling disk is exposed to a constant oscillating movement about the drum axis, which movement causes vibrations in the device and friction loads on the thread winding which are being wound around the drum.
In a device which is known from German OS No. 22 20 207 (and corresponding portions of U.S. Pat. No. 3,776,400), the advance of the thread windings is not done by a wobbling disk, but by rods which are operated by a complicated mechanism. As a holding mechanism there is provided coaxial toothed rims at the upper edge of the storage drum core and at the lower edge of the drive housing, and an angularly positioned toothed disk is inserted into the free space provided therebetween, which toothed disk is rotatably supported by a bearing on a sloped hub provided on the through-going shaft of the device. The toothed disk simultaneously wobbles on both toothed rims, from which results difficult engagement and rolling relationships, which during operation lead to vibrations. The device is complicated and lengthy in structure.
The basic purpose of this invention is to produce a thread-storage and delivery device of the above-mentioned type, which is characterized by a light weight and a short structural length, and which does not require any additional devices for holding the storage drum stationary in a soundless and vibrationless manner, this being accomplished by using the same parts which are required for the proper functioning of the device with simple additional provisions, thereby permitting a gentle thread advance.
The above purpose is attained in a device of the above-mentioned type through the characteristics defined in the attached claims.
In this invention, the advancing member required for the thread advance is additionally utilized as an active part for holding the storage drum stationary. Unlike the conventional device, the storage drum no longer holds the advancing member, but same is continuously coupled with the base member (i.e., specifically to an annular flange fixed to the base member, by braking and counterbraking elements) at a point which is offset relative to the feed element and is held by the base member. The storage drum is then supported against rotation by the advancing member. The thread feed, the winding up and unwinding of the thread, remains unaffected. Additional construction elements, as they are needed in the conventional device, are not needed. The device is thus compact and of light weight, and is distinguished by a simple structure and a short structural length. Unhindered access to the thread storage on the drum jacket is possible from all sides. Of particular importance is that the engagement between the advancing member and the annular flange occurs almost totally without any sound and without vibration, and that relative oscillating movements, which are damaging for the transport of the thread windings and during engagement, between the storage drum and the advancing member, do not occur. The given geometrical conditions result in an ideal rolling along of the outer section of the advancing member along the annular flange and in exact engagement conditions. Furthermore, the advantage is obtained that the braking elements and the counterbraking elements lie on these two cooperating parts on equal diameters, in relationship to the respective axis of rotation of each part. This makes the manufacture easier. Furthermore, a very advantageous and gentle movement of the thread during the wobbling movement of the advancing member is achieved, during which the outer section of the advancing member acts onto the thread windings in the advancing direction, since the outer section linearly moves the thread windings so that damaging friction does not occur between the outer section and the thread windings. This thus does not affect or influence the thread-unwinding tension which is to be kept constant. The gentle handling of the thread is thus an important aspect of the device.
A device for braking a fiber cable which is linearly blown at a high speed and for storing it without any speed in a can is known from BE Pat. No. 867,061, in which each winding of the fiber cable is moved downwardly by a spider positioned at an inclination with respect to the shaft of the device and thus wobbles during its rotation, which spider is provided on the periphery of a rod drum which is hindered against rotation and is stored in the can. The spider engages, with its radially outwardly projecting spoke ends, an internal tooth system of a ring which is coaxially arranged outside of the device and is prevented by said engagement against corotation therewith. Furthermore, the rods of the rod drum engage between the spokes, so that these are also held stationary. This conventional device cannot be compared with a thread-delivery and storage device of the type disclosed in this invention wherein a thread is intermittently unwound from a spool of a thread-delivery and storage device, is then wound up to form a thread storage on the drum surface, and is again unwound overhead from said drum over a specially constructed drum rim with a constant thread tension, whereby the rotatable parts are driven only when the formed thread storage is too small. Rather, the aforesaid conventional device continuously works with a quickly accumulated fiber cable and stores it in windings in a can, whereby same, if desired during an axial impressing on a coaxial cutting rim, is cut into individual fiber cable pieces. From the kinematics of this conventional device, it is necessary only that it stop the speed of the fiber cable. A vibrationless running of the wobbling disk, the exclusion of oscillating movements of the disk and of the braking surface, and free access to the braking surface are not desired. The spokes of the spider engage between the teeth of the stationary rim, while the rods of the rod drum engage between the spokes. The required clearance or play, and the line-shaped contact zones between the engaging parts, results in rough engaging and running conditions, which conditions are intolerable in a thread-storage and delivery device of the type according to the present invention.
In a preferred exemplary embodiment of the present inventive device, the braking and counterbraking elements achieve a positive coupling between the base flange and the advancing member. With this given form, locking occurs between the storage drum and the advancing member during each rotation of the storage drum, and oscillating rotation of the storage drum is reliably prevented.
In a further advantageous embodiment of an inventive device the "effective" rim area of the outer section of the advancing member rolls along on the underside of the flange, and projections are progressively inserted into depressions, whereby a uniform and quiet running can be achieved.
In a further advantageous embodiment the advancing member constantly rolls along with its outer section on the flange, and the use of a friction coating is sufficient for a reliable securing of the storage drum against rotation. Special vibration reduction and quiet running, with a constantly effective self-cleaning effect, result from this construction.
Measures for achieving quiet running and vibration reduction can be incorporated into the embodiment of the invention. The braking and counterbraking elements may consist of an elastic plastic which is solid enough to satisfactorily absorb the occurring forces, and which automatically compensates for possible deformations. Alternatively, it is possible to utilize a nonelastic plastic, preferably polyurethane such as Contilan (registered trademark), for the manufacture of the braking and counterbraking elements, if these receive a special form or shape. Such elements of a relatively nonelastic plastic then become elastic in themselves, if they are provided for example with through-holes or recesses. In such a configuration it is also possible to use nylon, which can be simply formed, for example by being pressed or injection molded.